1) Field of the Disclosure
The disclosure relates generally to systems and methods for machining structures, and more particularly, to improved systems and methods for back spotfacing of structures or parts, such as workpieces.
2) Description of Related Art
Spotfacing is a secondary mechanical process to machine, mill, or cut a surface, e.g., spotface, such as around an outside of a hole that has been previously drilled or formed in a structure, part, or workpiece, for example, a structure, part, or workpiece having an angled or curved surface to be spotfaced. Back spotfacing entails spotfacing a surface, e.g., back spotface, on the inside of the structure, or on the backside of the part or workpiece.
In spotfacing or back spotfacing, the hole may include, for example, a fastener hole, a bolt hole, a screw hole, or the like. The surface, e.g., spotface or back spotface, is perpendicular to the axis of the hole, and allows a head of the fastener, bolt, or screw, a nut, or another object to be seated on the surface, to be evenly tightened down on the surface.
Spotfacing and back spotfacing systems and methods may be used in a variety of applications. Such applications may include manufacturing of aircraft structures and parts, manufacturing of automobile parts, carpentry, woodworking, and other applications where a smooth and accurately located surface is desired.
Known systems and methods exist for back spotfacing the inside of structures. For example, one such known system and method for back spotfacing the inside of an aircraft structure requires the use of large tooling jigs to align large, heavy manual feed air motors to the previously drilled hole which used the same tooling. Such large equipment may be expensive to use and maintain and time consuming to set up, and may, in turn, result in increased manufacturing costs and increased time of manufacturing. In addition, such known system and method requires one or more additional workers to monitor the back spotfacing process from inside the structure. This may result in increased labor costs, and may, in turn, result in increased manufacturing costs. Moreover, having to monitor the back spotfacing process from inside the structure may involve the one or more additional workers being in a confined space near moving equipment, which may present ergonomic or safety issues.
In addition, due to fatigue and strength concerns, a cut depth of a spotface or back spotface made on an aircraft structure, part, or workpiece may require very tight tolerances and may need to meet certain cut depth requirements. For example, after obtaining a full circle cut in an aircraft part, it may only be possible to cut an additional 0.020 inch deeper to meet such cut depth requirements. Simply machining or cutting a deep spotface or back spotface may not be enough to meet such cut depth requirements. Further, although an additional worker may make a visual determination whether a minimum cut depth has been made to achieve a spotface or back spotface surface, such visual determination may not be precise. Thus, it is desirable to have a back spotfacing system and method that determines a precise cut depth prior to cutting.
Accordingly, there is a need in the art for an improved system and method for back spotfacing of structures, such as workpieces, that is simple to use, safe, cost effective, reliable, repeatable, and determines a precise cut depth, and that provides advantages over known systems and methods.